1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Generic Exynos Bus frequency driver with DEVFREQ Framework 4 * 5 * Copyright (c) 2016 Samsung Electronics Co., Ltd. 6 * Author : Chanwoo Choi <cw00.choi@samsung.com> 7 * 8 * This driver support Exynos Bus frequency feature by using 9 * DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c. 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/devfreq.h> 14 #include <linux/devfreq-event.h> 15 #include <linux/device.h> 16 #include <linux/export.h> 17 #include <linux/module.h> 18 #include <linux/of.h> 19 #include <linux/pm_opp.h> 20 #include <linux/platform_device.h> 21 #include <linux/regulator/consumer.h> 22 23 #define DEFAULT_SATURATION_RATIO 40 24 25 struct exynos_bus { 26 struct device *dev; 27 struct platform_device *icc_pdev; 28 29 struct devfreq *devfreq; 30 struct devfreq_event_dev **edev; 31 unsigned int edev_count; 32 struct mutex lock; 33 34 unsigned long curr_freq; 35 36 struct opp_table *opp_table; 37 struct clk *clk; 38 unsigned int ratio; 39 }; 40 41 /* 42 * Control the devfreq-event device to get the current state of bus 43 */ 44 #define exynos_bus_ops_edev(ops) \ 45 static int exynos_bus_##ops(struct exynos_bus *bus) \ 46 { \ 47 int i, ret; \ 48 \ 49 for (i = 0; i < bus->edev_count; i++) { \ 50 if (!bus->edev[i]) \ 51 continue; \ 52 ret = devfreq_event_##ops(bus->edev[i]); \ 53 if (ret < 0) \ 54 return ret; \ 55 } \ 56 \ 57 return 0; \ 58 } 59 exynos_bus_ops_edev(enable_edev); 60 exynos_bus_ops_edev(disable_edev); 61 exynos_bus_ops_edev(set_event); 62 63 static int exynos_bus_get_event(struct exynos_bus *bus, 64 struct devfreq_event_data *edata) 65 { 66 struct devfreq_event_data event_data; 67 unsigned long load_count = 0, total_count = 0; 68 int i, ret = 0; 69 70 for (i = 0; i < bus->edev_count; i++) { 71 if (!bus->edev[i]) 72 continue; 73 74 ret = devfreq_event_get_event(bus->edev[i], &event_data); 75 if (ret < 0) 76 return ret; 77 78 if (i == 0 || event_data.load_count > load_count) { 79 load_count = event_data.load_count; 80 total_count = event_data.total_count; 81 } 82 } 83 84 edata->load_count = load_count; 85 edata->total_count = total_count; 86 87 return ret; 88 } 89 90 /* 91 * devfreq function for both simple-ondemand and passive governor 92 */ 93 static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags) 94 { 95 struct exynos_bus *bus = dev_get_drvdata(dev); 96 struct dev_pm_opp *new_opp; 97 int ret = 0; 98 99 /* Get correct frequency for bus. */ 100 new_opp = devfreq_recommended_opp(dev, freq, flags); 101 if (IS_ERR(new_opp)) { 102 dev_err(dev, "failed to get recommended opp instance\n"); 103 return PTR_ERR(new_opp); 104 } 105 106 dev_pm_opp_put(new_opp); 107 108 /* Change voltage and frequency according to new OPP level */ 109 mutex_lock(&bus->lock); 110 ret = dev_pm_opp_set_rate(dev, *freq); 111 if (!ret) 112 bus->curr_freq = *freq; 113 114 mutex_unlock(&bus->lock); 115 116 return ret; 117 } 118 119 static int exynos_bus_get_dev_status(struct device *dev, 120 struct devfreq_dev_status *stat) 121 { 122 struct exynos_bus *bus = dev_get_drvdata(dev); 123 struct devfreq_event_data edata; 124 int ret; 125 126 stat->current_frequency = bus->curr_freq; 127 128 ret = exynos_bus_get_event(bus, &edata); 129 if (ret < 0) { 130 dev_err(dev, "failed to get event from devfreq-event devices\n"); 131 stat->total_time = stat->busy_time = 0; 132 goto err; 133 } 134 135 stat->busy_time = (edata.load_count * 100) / bus->ratio; 136 stat->total_time = edata.total_count; 137 138 dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time, 139 stat->total_time); 140 141 err: 142 ret = exynos_bus_set_event(bus); 143 if (ret < 0) { 144 dev_err(dev, "failed to set event to devfreq-event devices\n"); 145 return ret; 146 } 147 148 return ret; 149 } 150 151 static void exynos_bus_exit(struct device *dev) 152 { 153 struct exynos_bus *bus = dev_get_drvdata(dev); 154 int ret; 155 156 ret = exynos_bus_disable_edev(bus); 157 if (ret < 0) 158 dev_warn(dev, "failed to disable the devfreq-event devices\n"); 159 160 platform_device_unregister(bus->icc_pdev); 161 162 dev_pm_opp_of_remove_table(dev); 163 clk_disable_unprepare(bus->clk); 164 dev_pm_opp_put_regulators(bus->opp_table); 165 bus->opp_table = NULL; 166 } 167 168 static void exynos_bus_passive_exit(struct device *dev) 169 { 170 struct exynos_bus *bus = dev_get_drvdata(dev); 171 172 platform_device_unregister(bus->icc_pdev); 173 174 dev_pm_opp_of_remove_table(dev); 175 clk_disable_unprepare(bus->clk); 176 } 177 178 static int exynos_bus_parent_parse_of(struct device_node *np, 179 struct exynos_bus *bus) 180 { 181 struct device *dev = bus->dev; 182 struct opp_table *opp_table; 183 const char *vdd = "vdd"; 184 int i, ret, count, size; 185 186 opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1); 187 if (IS_ERR(opp_table)) { 188 ret = PTR_ERR(opp_table); 189 dev_err(dev, "failed to set regulators %d\n", ret); 190 return ret; 191 } 192 193 bus->opp_table = opp_table; 194 195 /* 196 * Get the devfreq-event devices to get the current utilization of 197 * buses. This raw data will be used in devfreq ondemand governor. 198 */ 199 count = devfreq_event_get_edev_count(dev, "devfreq-events"); 200 if (count < 0) { 201 dev_err(dev, "failed to get the count of devfreq-event dev\n"); 202 ret = count; 203 goto err_regulator; 204 } 205 bus->edev_count = count; 206 207 size = sizeof(*bus->edev) * count; 208 bus->edev = devm_kzalloc(dev, size, GFP_KERNEL); 209 if (!bus->edev) { 210 ret = -ENOMEM; 211 goto err_regulator; 212 } 213 214 for (i = 0; i < count; i++) { 215 bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, 216 "devfreq-events", i); 217 if (IS_ERR(bus->edev[i])) { 218 ret = -EPROBE_DEFER; 219 goto err_regulator; 220 } 221 } 222 223 /* 224 * Optionally, Get the saturation ratio according to Exynos SoC 225 * When measuring the utilization of each AXI bus with devfreq-event 226 * devices, the measured real cycle might be much lower than the 227 * total cycle of bus during sampling rate. In result, the devfreq 228 * simple-ondemand governor might not decide to change the current 229 * frequency due to too utilization (= real cycle/total cycle). 230 * So, this property is used to adjust the utilization when calculating 231 * the busy_time in exynos_bus_get_dev_status(). 232 */ 233 if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio)) 234 bus->ratio = DEFAULT_SATURATION_RATIO; 235 236 return 0; 237 238 err_regulator: 239 dev_pm_opp_put_regulators(bus->opp_table); 240 bus->opp_table = NULL; 241 242 return ret; 243 } 244 245 static int exynos_bus_parse_of(struct device_node *np, 246 struct exynos_bus *bus) 247 { 248 struct device *dev = bus->dev; 249 struct dev_pm_opp *opp; 250 unsigned long rate; 251 int ret; 252 253 /* Get the clock to provide each bus with source clock */ 254 bus->clk = devm_clk_get(dev, "bus"); 255 if (IS_ERR(bus->clk)) { 256 dev_err(dev, "failed to get bus clock\n"); 257 return PTR_ERR(bus->clk); 258 } 259 260 ret = clk_prepare_enable(bus->clk); 261 if (ret < 0) { 262 dev_err(dev, "failed to get enable clock\n"); 263 return ret; 264 } 265 266 /* Get the freq and voltage from OPP table to scale the bus freq */ 267 ret = dev_pm_opp_of_add_table(dev); 268 if (ret < 0) { 269 dev_err(dev, "failed to get OPP table\n"); 270 goto err_clk; 271 } 272 273 rate = clk_get_rate(bus->clk); 274 275 opp = devfreq_recommended_opp(dev, &rate, 0); 276 if (IS_ERR(opp)) { 277 dev_err(dev, "failed to find dev_pm_opp\n"); 278 ret = PTR_ERR(opp); 279 goto err_opp; 280 } 281 bus->curr_freq = dev_pm_opp_get_freq(opp); 282 dev_pm_opp_put(opp); 283 284 return 0; 285 286 err_opp: 287 dev_pm_opp_of_remove_table(dev); 288 err_clk: 289 clk_disable_unprepare(bus->clk); 290 291 return ret; 292 } 293 294 static int exynos_bus_profile_init(struct exynos_bus *bus, 295 struct devfreq_dev_profile *profile) 296 { 297 struct device *dev = bus->dev; 298 struct devfreq_simple_ondemand_data *ondemand_data; 299 int ret; 300 301 /* Initialize the struct profile and governor data for parent device */ 302 profile->polling_ms = 50; 303 profile->target = exynos_bus_target; 304 profile->get_dev_status = exynos_bus_get_dev_status; 305 profile->exit = exynos_bus_exit; 306 307 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL); 308 if (!ondemand_data) 309 return -ENOMEM; 310 311 ondemand_data->upthreshold = 40; 312 ondemand_data->downdifferential = 5; 313 314 /* Add devfreq device to monitor and handle the exynos bus */ 315 bus->devfreq = devm_devfreq_add_device(dev, profile, 316 DEVFREQ_GOV_SIMPLE_ONDEMAND, 317 ondemand_data); 318 if (IS_ERR(bus->devfreq)) { 319 dev_err(dev, "failed to add devfreq device\n"); 320 return PTR_ERR(bus->devfreq); 321 } 322 323 /* Register opp_notifier to catch the change of OPP */ 324 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq); 325 if (ret < 0) { 326 dev_err(dev, "failed to register opp notifier\n"); 327 return ret; 328 } 329 330 /* 331 * Enable devfreq-event to get raw data which is used to determine 332 * current bus load. 333 */ 334 ret = exynos_bus_enable_edev(bus); 335 if (ret < 0) { 336 dev_err(dev, "failed to enable devfreq-event devices\n"); 337 return ret; 338 } 339 340 ret = exynos_bus_set_event(bus); 341 if (ret < 0) { 342 dev_err(dev, "failed to set event to devfreq-event devices\n"); 343 goto err_edev; 344 } 345 346 return 0; 347 348 err_edev: 349 if (exynos_bus_disable_edev(bus)) 350 dev_warn(dev, "failed to disable the devfreq-event devices\n"); 351 352 return ret; 353 } 354 355 static int exynos_bus_profile_init_passive(struct exynos_bus *bus, 356 struct devfreq_dev_profile *profile) 357 { 358 struct device *dev = bus->dev; 359 struct devfreq_passive_data *passive_data; 360 struct devfreq *parent_devfreq; 361 362 /* Initialize the struct profile and governor data for passive device */ 363 profile->target = exynos_bus_target; 364 profile->exit = exynos_bus_passive_exit; 365 366 /* Get the instance of parent devfreq device */ 367 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0); 368 if (IS_ERR(parent_devfreq)) 369 return -EPROBE_DEFER; 370 371 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL); 372 if (!passive_data) 373 return -ENOMEM; 374 375 passive_data->parent = parent_devfreq; 376 377 /* Add devfreq device for exynos bus with passive governor */ 378 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE, 379 passive_data); 380 if (IS_ERR(bus->devfreq)) { 381 dev_err(dev, 382 "failed to add devfreq dev with passive governor\n"); 383 return PTR_ERR(bus->devfreq); 384 } 385 386 return 0; 387 } 388 389 static int exynos_bus_probe(struct platform_device *pdev) 390 { 391 struct device *dev = &pdev->dev; 392 struct device_node *np = dev->of_node, *node; 393 struct devfreq_dev_profile *profile; 394 struct exynos_bus *bus; 395 int ret, max_state; 396 unsigned long min_freq, max_freq; 397 bool passive = false; 398 399 if (!np) { 400 dev_err(dev, "failed to find devicetree node\n"); 401 return -EINVAL; 402 } 403 404 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); 405 if (!bus) 406 return -ENOMEM; 407 mutex_init(&bus->lock); 408 bus->dev = &pdev->dev; 409 platform_set_drvdata(pdev, bus); 410 411 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL); 412 if (!profile) 413 return -ENOMEM; 414 415 node = of_parse_phandle(dev->of_node, "devfreq", 0); 416 if (node) { 417 of_node_put(node); 418 passive = true; 419 } else { 420 ret = exynos_bus_parent_parse_of(np, bus); 421 if (ret < 0) 422 return ret; 423 } 424 425 /* Parse the device-tree to get the resource information */ 426 ret = exynos_bus_parse_of(np, bus); 427 if (ret < 0) 428 goto err_reg; 429 430 if (passive) 431 ret = exynos_bus_profile_init_passive(bus, profile); 432 else 433 ret = exynos_bus_profile_init(bus, profile); 434 435 if (ret < 0) 436 goto err; 437 438 /* Create child platform device for the interconnect provider */ 439 if (of_get_property(dev->of_node, "#interconnect-cells", NULL)) { 440 bus->icc_pdev = platform_device_register_data( 441 dev, "exynos-generic-icc", 442 PLATFORM_DEVID_AUTO, NULL, 0); 443 444 if (IS_ERR(bus->icc_pdev)) { 445 ret = PTR_ERR(bus->icc_pdev); 446 goto err; 447 } 448 } 449 450 max_state = bus->devfreq->profile->max_state; 451 min_freq = (bus->devfreq->profile->freq_table[0] / 1000); 452 max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000); 453 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n", 454 dev_name(dev), min_freq, max_freq); 455 456 return 0; 457 458 err: 459 dev_pm_opp_of_remove_table(dev); 460 clk_disable_unprepare(bus->clk); 461 err_reg: 462 dev_pm_opp_put_regulators(bus->opp_table); 463 bus->opp_table = NULL; 464 465 return ret; 466 } 467 468 static void exynos_bus_shutdown(struct platform_device *pdev) 469 { 470 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev); 471 472 devfreq_suspend_device(bus->devfreq); 473 } 474 475 #ifdef CONFIG_PM_SLEEP 476 static int exynos_bus_resume(struct device *dev) 477 { 478 struct exynos_bus *bus = dev_get_drvdata(dev); 479 int ret; 480 481 ret = exynos_bus_enable_edev(bus); 482 if (ret < 0) { 483 dev_err(dev, "failed to enable the devfreq-event devices\n"); 484 return ret; 485 } 486 487 return 0; 488 } 489 490 static int exynos_bus_suspend(struct device *dev) 491 { 492 struct exynos_bus *bus = dev_get_drvdata(dev); 493 int ret; 494 495 ret = exynos_bus_disable_edev(bus); 496 if (ret < 0) { 497 dev_err(dev, "failed to disable the devfreq-event devices\n"); 498 return ret; 499 } 500 501 return 0; 502 } 503 #endif 504 505 static const struct dev_pm_ops exynos_bus_pm = { 506 SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume) 507 }; 508 509 static const struct of_device_id exynos_bus_of_match[] = { 510 { .compatible = "samsung,exynos-bus", }, 511 { /* sentinel */ }, 512 }; 513 MODULE_DEVICE_TABLE(of, exynos_bus_of_match); 514 515 static struct platform_driver exynos_bus_platdrv = { 516 .probe = exynos_bus_probe, 517 .shutdown = exynos_bus_shutdown, 518 .driver = { 519 .name = "exynos-bus", 520 .pm = &exynos_bus_pm, 521 .of_match_table = of_match_ptr(exynos_bus_of_match), 522 }, 523 }; 524 module_platform_driver(exynos_bus_platdrv); 525 526 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver"); 527 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>"); 528 MODULE_LICENSE("GPL v2"); 529